[gnome-photos/gnome-3-16] preview-nav-buttons: Re-evaluate the ability to navigate at each step

[Debarshi Ray <debarshir src gnome org>]

commit d8fccc0bffee5685bb48e1a09d5d2812af02ea24
Author: Debarshi Ray <debarshir gnome org>
Date:   Sun Mar 15 01:01:45 2015 +0100

    preview-nav-buttons: Re-evaluate the ability to navigate at each step
    
    We only call photos_preview_nav_buttons_show when we first move to the
    preview, instead of every time a GeglNode is set. This is logical since
    we don't want to affect the visibility of the buttons as we navigate.
    However, we need to re-evaluate the ability to navigate in each
    direction after every step. Otherwise the controls won't match the
    realities of our location within the model.
    
    There was an earlier broken attempt to address this in
    113d48bc7ea6a3cc7e40bd2fec1e6a85684e942f and it became worse after
    949246eab98663c8d84d575cbe785f982f4c5de0
    
    https://bugzilla.gnome.org/show_bug.cgi?id=746152

 src/photos-preview-nav-buttons.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/photos-preview-nav-buttons.c b/src/photos-preview-nav-buttons.c
index 0f9b005..9af5d29 100644
--- a/src/photos-preview-nav-buttons.c
+++ b/src/photos-preview-nav-buttons.c
@@ -518,6 +518,7 @@ photos_preview_nav_buttons_next (PhotosPreviewNavButtons *self)
   priv->action = PHOTOS_PREVIEW_ACTION_NEXT;
   gtk_tree_path_next (priv->current_path);
   photos_preview_nav_buttons_set_active_path (self);
+  photos_preview_nav_buttons_update_visibility (self);
 
   g_signal_emit (self, signals[ACTIVATED], 0, priv->action);
 }
@@ -534,6 +535,7 @@ photos_preview_nav_buttons_previous (PhotosPreviewNavButtons *self)
   priv->action = PHOTOS_PREVIEW_ACTION_PREVIOUS;
   gtk_tree_path_prev (priv->current_path);
   photos_preview_nav_buttons_set_active_path (self);
+  photos_preview_nav_buttons_update_visibility (self);
 
   g_signal_emit (self, signals[ACTIVATED], 0, priv->action);
 }